1. Field of the Invention
The present invention relates to a phenolic resin composite material, which is good in terms of heat resistance, etc., and which is applicable to automotive component parts, aircraft component parts, component parts for electric and electronic instruments, materials for architecture, and so on.
2. Description of the Related Art
Phenolic resins have been used widely in resinous molded products, but most of them have been used as composite materials. Specifically, in order to improve the mechanical strengths of the resinous molded products, organic fillers, such as cotton, wooden powders, etc., inorganic fibers, such as glass fibers, carbon fibers, etc., and further inorganic fillers, such as clays, calcium carbonate, etc., have been mixed in phenolic resins.
However, even when inorganic materials, and the like, are simply added and mixed in phenolic resins, the inorganic materials bond very weakly with the phenolic resins which make a mother phase. Accordingly, when fillers are added to phenolic resins, it might be probable to cause a problem in that the resulting composite materials are embrittled, or the like.
Therefore, in order to strengthen the bonding between phenolic resins and inorganic materials, it has been know to treat inorganic materials with silane coupling agents, for example. Even in such a case, however, the bonding between them is exerted by the van der Waals force, and is improved to such an extent only that the affinity arises between them. Thus, in conventional phenolic resin composite materials, it has not been possible to sufficiently improve the reinforcement effect and heat resistance by the addition of inorganic materials.
In Japanese Patent Publication No. 3,014,674, there is a disclosure on a composite material in which a layered clay mineral is dispersed in a phenolic resin. Specifically, in the examples, a composite material is disclosed in which a layered clay mineral (e.g., montmorillonite), being turned into an onium salt, is mixed in a phenolic resin. In the case of the composite material, since the phenolic resin and the layered clay mineral are bonded by ion bond, by hydrogen bond or by both of them, the composite material is said to exhibit better mechanical strengths and heat resistance.
However, even such a phenolic composite material has been still insufficient in terms of the mechanical strengths, especially, in terms of the high temperature strength. Consequently, there have been demands for phenolic composite materials which can exhibit much better heat resistance.